Guava
Introduction
The guava (Psidium guajava) is a small evergreen, native
of tropical America. It was noted by the early European explorers
in Mexico and Peru and is now widely grown throughout the
tropics. It is a member of the dicotyledon family Myrtaceae,
along with pimento (all spice), cinnamon, clove and nutmeg.
In 1981, total world production was about 500,000 metric tons
of fresh fruit of which India produced 165,000 and Jamaica 3000.
There are a number of different species and numerous cultivars
ranging from white-fleshed sweet types to pink-fleshed sour
types.
Chemistry
Sugars
Carbohydrates are the principal nonaqueous constituents of guava
totalling about 14.8 g/ 100 g of fruit pulp. Of this nearly 6 g
is made up of fructose (58.9%), glucose (35.7) and sucrose(
5.3%).
Acids
The total acidity of a range of guavas has been quoted as between
14-18 mg per 100 g and ascorbic acid was found to vary between
62-364 mg/ 100 g. The tartness of guavas has been acsribed to the
pH of around 3-4 which comes about largely due to the presence of
malic and citric acids.
Pigments
The lycopene content of the Beaumont variety has been found to be
about 5-7 mg/100 g fruit. This gives rise to the pink
colouration.
Volatiles
Over 150 compounds have been identified in the volatile flavour
constituents of guavas. Some of these include:
References
"Tropical Fruit Processing", Edited by J. Jagtiani, H.T. Chan,
Jr. and W.S. Sakai Food Science and Technology, A series of
monographs, 1988, Academic Press, Inc., 1250 Sixth Avenue, San
Diego, California, 92101.
"Food Flavourings", Edited by P.R. Ashurst, Blackie Academic
& Professional, an imprint of Chapman & Hall, Wester
Cleddens Road, Bishopbriggs, Glascow, G64 2NZ, UK. 2nd edit.
1995.
Return to links to the chemistry of other Jamaican items, including
spices and fruit and vegetables.
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Lancashire, all rights reserved.
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Lancashire,
The Department of Chemistry, University of the West Indies,
Mona Campus, Kingston 7, Jamaica.
Created May 1997. Links checked and/or last
modified 8th August 2014.
URL
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